Sense and Avoid Characterization of the Independent Configurable Architecture for Reliable Operations of Unmanned Systems

AbstractIndependent Configurable Architecture for Reliable Operations of Unmanned Systems (ICAROUS) is a distributed software architecture developed by NASA Langley Research Center to enable safe autonomous UAS operations. ICAROUS consists of a collection formally verified core algorithms for path planning, traffic avoidance, geofence handling, and decision making that interface with an autopilot system through a publisher-subscriber middleware. The ICAROUS Sense and Avoid Characterization (ISAAC) test was designed to evaluate the performance of the onboard Sense and Avoid (SAA) capability to detect potential conflicts with other aircraft and autonomously maneuver to avoid collisions, while remaining within the airspace boundaries of the mission. The ISAAC tests evaluated the impact of separation distances and alerting times on SAA performance. A preliminary analysis of the effects of each parameter on key measures of performance is conducted, informing the choice of appropriate parameter values for different small Unmanned Aircraft Systems (sUAS) applications. Furthermore, low-power Automatic Dependent Surveillance Broadcast (ADS-B) is evaluated for potential use to enable autonomous sUAS to sUAS deconflictions as well as to provide usable warnings for manned aircraft without saturating the frequency spectrum

A novel optical sensing lab-on-a-disc platform for chromium speciation

The determination chromium speciation in the field is a significant analytical challenge. While chromium exists in oxidation states from 0 to VI, it is predominantly found in the (III) and (VI) states [1]. Industry effluent (e.g. textile/electroplating) is a common source of chromium pollution in the environment. Due to corrosion inhibitors used in pipes, and contamination leaching from sanitary landfills, drinking water supplies can become contaminated also [2]. The bioavailability and toxicity of chromium is largely dependent the oxidation state of the element [2]. Consumption of Cr (III) is an essential component in human diet, as it is responsible for maintaining glucose, lipid and protein metabolism [3]. In contrast, Cr (VI) is strongly oxidizing, exhibiting high toxicity, with carcinogenic and mutagenic properties [4]. It is recommended by the World Health Organisation (WHO) that the maximum allowable concentration of chromium (VI) in drinking water is 0.05 mg L−1 [5]. Handheld colourimeters for on-site measurements are a convenient option for frequent water monitoring; however the limit of detection (LOD) of these devices is typically higher than the recommended limit. Microfluidic ‘lab-on-a-disc’ technologies were used in the development of an optical sensor for chromium speciation in water. The principal behind these devices is to minimize laboratory processes onto a microfluidic system that can be brought to the sampling site for rapid sample-to-answer analyses. The objective for this device was to design and fabricate a fully integrated optical sensor for on-site measurement of both trivalent and hexavalent chromium in freshwater. A strong focus was placed on maximizing sensitivity in order to achieve a low LOD

Design features for enhancing optical detection on lab-on-a-disc platforms

Centrifugal microfluidics has undergone a massive growth surge over the past 15 years, evident by the number of comprehensive reviews currently available, with special regard towards Lab-On-A-Disc (LOAD) diagnostic solutions.1–3 The potential of a LOAD system is dependent on its ability to mimic the specific laboratory protocols with which are required to conduct sample-to-answer analysis. This would include sample handling and manipulation (such as mixing and separation), sample modification (including heating and redox reactions), as well as reaction detection (such as optical, electrochemical, or as required by user). Optical detection strategies on LOAD platforms has been largely successful in both the fields of biological and chemical sensing.4 Herein, will demonstrate the optical optimisations which were carried out on a biological fluorescent-based5 and a chemical absorbance-based6 LOAD detection platforms. This will include the identification and optimisation of LED-photodiode selection, the effects of detection orientation and pathway-length fluorophore selection. Also covered will be a comparison between the microfluidic architecture for incorporating either detection methods as well as their reported limits of detection

Development of novel gas sensors

Of all human senses our ability to detect odours may be the least appreciated and certainly the least understood [1], and yet is one o f the most powerful. Humans can only see a narrow region o f the light spectrum (300-700 ran), hear a small range in the frequency spectrum (20-20KHz), touch objects that are close. The smell and taste o f substances however can give us much more information about an objects nature. However quantifying these senses is difficult. The taste o f substances has been provisionally classed as being Sour, Bitter, Sweet or Salty. Smells have been classed as being camphoraceous, ethereal, floral, minty, musky, pungent or putrid [2], but this has been described as being over simplistic [3], Therefore to mimic the nose it is necessary to understand how the nose function

In States We Trust : Self-Settled Trusts, Public Policy, and Interstate Federalism

Over the last twenty years, domestic asset protection trusts have risen in popularity as a means of estate planning and asset protection. A domestic asset protection trust is an irrevocable trust formed under state law which enables an independent trustee to allocate money to a class of persons, which includes the settlor. Since Alaska first enacted domestic asset protection legislation in 1997, fifteen states have followed its lead. The case law over the last twenty years addressing these trust mechanisms has, however, been surprisingly sparse. A Washington bankruptcy court decision, In re Huber, altered this drought, but caused more confusion by holding that a public policy exception trumped standard choice of law analysis. The end result: The court applied the law of the settlor’s state, which prohibited these trusts, rather than the law of Alaska, where the trust actually originated. This Note argues that the Huber decision was wrongly decided and provides a framework for future courts considering the choice of law issues related to domestic asset protection trusts. This Note also demonstrates that economic, public policy, and federalism considerations support the choice of law outcome

Autonomous sensors for nutrient monitoring

Cultural eutrophication is the process whereby a body of water becomes over-enriched with nutrients, in particular nitrogen (N) and phosphorus (P), resulting in algal blooms and subsequent death and decomposition which deplete oxygen levels in the water (i.e. hypoxia), leading to the loss of aquatic animals (e.g. fishes). This is caused by excess N and P. Agriculture is the major source to Irish rivers and estuaries, with 70% of P loads and 82% of N loads attributed to agricultural sources . Hypoxia in the Gulf of Mexico has been linked to excessive N loading. Nuisance algal blooms in Lake Erie have been linked to agricultural P. Previous efforts have concentrated on measuring agricultural runoff directly using grab samples or spot measurements, but high frequency sampling will be essential to accurately characterize the extent and temporal resolution of agricultural impacts. Low cost real-time nutrient sensors are critical for quantifying the influence of agriculture on freshwater, and more broadly, for effective water management throughout Irish, European, and American river basins

Building a Systems View of Strategic Discourse across Organizational Meetings

The purpose of this paper is to explore and expand the theoretical resources available to conceptualise organisational strategy meetings as a ‘system’, rather than as singular strategic events or episodes. The paper begins by reviewing the Meetings literature to explore the existing theoretical guidance on conceptualising meetings as a collective and integrated set of activities, rather than as singular events in isolation of each other. The Systems literature is reviewed to identify concepts which may be adopted to enable a systematised view of meetings. The central focus of the paper is to explore the theoretical ways through which organisations’ meetings could be conceptualised as an integrated ‘system of meetings’, rather than as single events. An outline of the empirical data source is then provided, along with the methodology adopted to record and analyse the data

Sol-gel Characteristics for Corrosion Resistance of Anodised Aluminium

Conventional anodising electrolytes based on sulphuric acid, oxalic acid and phosphoric acid have been used to form nanoporous layers on AA3003-H14 and sealed with silane based sol-gel sealers. It is shown that the sol-gel chemistries have varying levels of pore penetration depending on the synthesis conditions. The extent of sol-gel penetration and pore sealing is analysed by electron microscopy and energy dispersive x-ray spectroscopy. To describe the sealing phenomena observed a sol-gel penetration and sealing rating has been proposed to explain the interactions of the sol-gels with the pores of the anodised layers. The corrosion resistance of the sol-gel sealed anodised aluminium surfaces was evaluated using neutral salt spray testing and electrochemical impedance spectroscopy